It has been said time and again on these forums that it is not possible to backlight an eInk screen. When a friend of mine told me he was considering a Samsung Alias2, with an eInk keypad that changes for different functions I asked about how it would be used in the dark, which he often needs to do as a plumber working in basements and cramped spaces. He kindly informed me that it was backlit, and pointed me to a video (http://www.engadget.com/2009/05/08/video-samsung-alias-2-dynamic-e-ink-keypad-in-action/).

Looking at the vid, it does appear to be backlit, yet I thought people had made it clear on these forums that this was not possible. Anyone know what Samsung is doing differently?

The Bandit

Are you sure it is e-ink? It looks like the screen of an iphone.

Engadget started the EInk "rumour" because the key labels can change (Samsung Phone with EInk Keyboard (http://www.mobileread.com/forums/showthread.php?t=45970)), but if it has back lighting that seems unlikely.

While eInk does not require backlighting to work, nothing really prohibits the eInk from being back lit. I suspect more eInk devices in the future will have some sort of lighting mechanism.

=X=

I'd always thought that back-lighting required a transmissive display (i.e. one that relied on light passing through it to generate the image), and that e-ink was a reflective display, i.e. that light was reflected from it. Whilst being a reflective display doesn't preclude lighting, I'd assumed that it would not then be a back-lit, but instead a front-lit display (e.g. as the Sony accessory does). Or have I misunderstood something (decidedly possible!)?

There are filters/surfaces/film that reflect light on one side and allow light to pass through on another side. It's not far fetch to imaging an eInk device using such a material.

=X=

My dream screen would be a backlit e-ink screen.

Do we know it's not a lightwedge type screen? Lit from the side, like the Sony PRS 700?

It appears from the web pages I looked at that they are talking about the keypad being e-ink or e-paper (making the keys changeable), not the screen part. The screen is in color, so probably not e-ink.

My dream screen would be a backlit e-ink screen.

It is not possible to backlight an e-INK screen as the light cannot show through since the ink is not transparent. However other e-Paper technologies might be able to support a transparent screen that could be backlit. You would have to study the various techniques, one is bi-stable LCD.

Dale

Yes, this looks to be a kind of LCD. That is definitely backlighting (look at the dark keys when the lights go on and off).

Well, I still don't get it. They are definitely claiming it is eInk, or as they put it: "Magic Keypad with E–Ink Technology." I suppose it could be an illuminated film as =X= suggests. Looks nice. Certainly brings up some interesting possibilities.

The Bandit

Is Samsung saying "Magic Keypad with E-Ink Technology" or are reviews/blogs saying that? (I looked around and didn't see a Samsung advert, but I didn't look that hard)

-MJ

While eInk does not require backlighting to work, nothing really prohibits the eInk from being back lit.

The fact that an eInk screen is opaque rather does prohibit it ;).

Is Samsung saying "Magic Keypad with E-Ink Technology" or are reviews/blogs saying that? (I looked around and didn't see a Samsung advert, but I didn't look that hard)

The quote is from the details tab on Verizon's product page (I think they are theonly US carrier selling this model). I could not find any information at Samsung either.

The Bandit

Check out this link from Crunchgear:

http://www.crunchgear.com/2009/05/11/the-samsung-alias-2-launches-today/

Looks like the keyboard is what is eInk:

"The phone sports a keyboard that, through the magic of e-ink, changes to meet the phone’s usage. It displays a standard number keypad when in normal phone mode and a QWERTY keyboard when in texting mode. Amazing."

The quote is from the details tab on Verizon's product page (I think they are theonly US carrier selling this model). I could not find any information at Samsung either.

The Bandit

Hrmm, ok... Well I went back and looked at that video and since the keys shapes don't change there is most likely an overlay, which means there is a transparent skin over the keys, these could be sidelit... That is if we are talking about one panel, if we are talking lots of little ones then they could be backlit through the gaps... Just some theories based on what I know of the technology and looking at it... ;)

-MJ

Hrmm, ok... Well I went back and looked at that video and since the keys shapes don't change there is most likely an overlay, which means there is a transparent skin over the keys, these could be sidelit... That is if we are talking about one panel, if we are talking lots of little ones then they could be backlit through the gaps... Just some theories based on what I know of the technology and looking at it... ;)

-MJ

that's what I think to, side lighting like the prs 700

if you watch the video the light turns on and off, the intensity of the black doesn't change a whole lot..


Verizon locks down their phones like crazy though, and this isn't running andriod or the new palmos, or an Iphone, or a blackberry, or even winos. buying a smart phone without those things is just dumb

The fact that an eInk screen is opaque rather does prohibit it ;).

Harry, let me ask you a question that I've wondered about for a while now. Does the screen necessarily have to be opaque? Can't the plastic be made semi-transparent? Then a light under it would be perfect, sort of glowing through to light it up.

that's what I think to, side lighting like the prs 700


I hate the side lighting, but it is the easiest to incorporate so far. I really loved the back light on my old EBW1150. Yes, I know, eyestrain blah blah blah. But my eyes are bad enough that pretty much everything strains them anyway, so it might as well be brightly lit.

that's what I think to, side lighting like the prs 700

if you watch the video the light turns on and off, the intensity of the black doesn't change a whole lot..


Verizon locks down their phones like crazy though, and this isn't running andriod or the new palmos, or an Iphone, or a blackberry, or even winos. buying a smart phone without those things is just dumb

I just watched the video again in HQ, it definitely looks backlit. The blacks lighten, the keys are not evenly lit, and there is a clear gradual shading from the hinge to the other side of the keypad. The keys flash to white before switching, but not black.

It does not seem to be E-ink.

I just watched the video again in HQ, it definitely looks backlit. The blacks lighten, the keys are not evenly lit, and there is a clear gradual shading from the hinge to the other side of the keypad. The keys flash to white before switching, but not black.

It does not seem to be E-ink.

They 'say' it's e-ink. But even so, I'm wondering at the usefulness of it. Maybe, however, it's a choleric display? (Cholesteric?)

Derek

They 'say' it's e-ink. But even so, I'm wondering at the usefulness of it. Maybe, however, it's a choleric display? (Cholesteric?)

Derek

viewable in sunlight is why eink, + changeable display.

and I certainly does look sidelighted, and it is e-ink from what I can tell.

it don't matter though. it's a crappy phone, on a crappy overpriced network

Harry, let me ask you a question that I've wondered about for a while now. Does the screen necessarily have to be opaque? Can't the plastic be made semi-transparent? Then a light under it would be perfect, sort of glowing through to light it up.

I suspect that, due to the way that eInk works, it has to be opaque. If the little "capsules" that form that image were not opaque, you wouldn't get "solid" text on the screen.

I'll run up to the Verizon store and see if they have that phone, check it out, and report back in a couple of hours.

I'm due for an upgrade, too bad it's not a smartphone.

Yes, the inner keyboard in e-ink but with lower contrast than any e-ink reader. It is *not* backlit, more accurately side or edge lit. The e-ink screen is covered with a bubble membrane where individual bubbles are the discreet keys. The light is between the e-ink screen and the membrane.

It is a very nice application because with this phone you can can open it in either of two directions. When it's opened as a traditional flip phone you have a properly oriented keyboard with the expected numerical keypad. Turn the phone on its side and open it on the long side and the keyboard changes to a QWERTY style. Great for texting.

Hope this answers the questions.

The fact that an eInk screen is opaque rather does prohibit it ;).
Tsk tsk harry such short sightedness will get you no where :). I said "eInk technology" not "eInk implementation".

Today's eInk might be opaque on both sides but future eInk screens may only be opaque on one side much like two way mirrors are today.

Harry, let me ask you a question that I've wondered about for a while now. Does the screen necessarily have to be opaque? Can't the plastic be made semi-transparent? Then a light under it would be perfect, sort of glowing through to light it up.

Right now the pixel in an eInk technology has two electro planes and two dies. The top electro plane is transparent the bottom is opaque.

One solution to enable backlighting to work is for the pixel would have to have 4 electro planes. Two on the top/bottom and one on each side. The top remains transparent. The bottom becomes a two way filter (opaque on the side of the die, transparent on the side if the back light source).

The eInk would operate as normal until backlighting is turned on. At this point instead of the the white die being brought to the top to simulate a white surface, the side electros are turned on to allow the back light to travel through the pixel to produce a white surface.


=X=

Right now the pixel in an eInk technology has two electro planes and two dies. The top electro plane is transparent the bottom is opaque.

One solution to enable backlighting to work is for the pixel would have to have 4 electro planes. Two on the top/bottom and one on each side. The top remains transparent. The bottom becomes a two way filter (opaque on the side of the die, transparent on the side if the back light source).

The eInk would operate as normal until backlighting is turned on. At this point instead of the the white die being brought to the top to simulate a white surface, the side electros are turned on to allow the back light to travel through the pixel to produce a white surface.


=X=

so, as I understand it you are saying that the bistable e-INK is quad stable with the w/b ink being up/down or the w/b ink being sideways (rotated 90 degree) in the cell allowing the light to shine through. Thus only the white areas would light up with the black areas blocking the light. How would you do gray?

Dale

so, as I understand it you are saying that the bistable e-INK is quad stable with the w/b ink being up/down or the w/b ink being sideways (rotated 90 degree) in the cell allowing the light to shine through. Thus only the white areas would light up with the black areas blocking the light. How would you do gray?

Dale

A pixel is covered by an electro plane where 1/2 - (white) and 1/2 + (black). To get gray with backlighting apply a + voltage on the top and a - on the side. The mixture of light and black will give you gray.
=X=

I'll run up to the Verizon store and see if they have that phone, check it out, and report back in a couple of hours.

I'm due for an upgrade, too bad it's not a smartphone.

Yes, the inner keyboard in e-ink but with lower contrast than any e-ink reader. It is *not* backlit, more accurately side or edge lit. The e-ink screen is covered with a bubble membrane where individual bubbles are the discreet keys. The light is between the e-ink screen and the membrane.

It is a very nice application because with this phone you can can open it in either of two directions. When it's opened as a traditional flip phone you have a properly oriented keyboard with the expected numerical keypad. Turn the phone on its side and open it on the long side and the keyboard changes to a QWERTY style. Great for texting.

Hope this answers the questions.


Ah, so they are not individual keys? Then they are just sitting way down below the light, thus why we see the shading. The videos seemed to show that they were individual keys.

Also, the black seemed to glow, maybe that is from the color of light they are using.